I don't think you should use Apple to put upgrade pricing in perspective. They've used inflated pricing to extract extra money from a captive audience for many years. Other OEMs cannot demand similar premiums for commodity products.
They use on-SoC RAM chips, essentially a cheaper HBM instead of just some random SO-DIMMS.
I think a better comparison would be Dell or Lenovo who do the same thing HP does, and they too charge a lot for what are essentially OEM versions of Samsung and Hynix memory anyone can get.
Well linux on desktop mostly just works. Linux on laptops has been a headache for a while with awful battery life, trackpad issues, wifi issues and things like that. So personally I don't feel the need for any dedicated linux desktop release compared to the laptop space where I appreciate more of a guarantee that the drivers actually work and I won't spend all my time messing with linux internals trying to get it to work.
Not sure, what do other laptops in the same price segment offer these days? I admit it's been a while since I looked, but I really doubt anyone has 32gb on a 1000 dollars laptop, or even 1500.